This invention relates to multiple station machines for producing concrete pipe and other similar concrete products.
There are known and used in the industry numerous designs of machines for producing concrete pipe and other similar products. Some of these machines are single station machines, while others are multiple station machines. The latter type machines generally have three stations at which the basic cycles of filling, pressure-heading and stripping are simultaneously performed. With the conventional multiple station machine, a module for each station is secured to a turntable that is usually mounted below the floor level. A jacket with a removable pallet secured to its lower end is lowered over the core at each station, and the annular space between the core and jacket is then filled with concrete at the filling station while the jacket is vibrated. The turntable is then rotated so that the filled form is at the pressure heading station where a pressure head is lowered on to the top of the form to compact the concrete. Vibration is generally completed at the pressure heading station, and preferably the pressure-head is equipped with a tongue-trowel which revolves the top joint frame during vibration to produce a smooth, trowel-finished joint. At the third station, the jacket and pallet together with the now-formed concrete pipe is stripped form the core and moved to the curing area. The jacket is then released from the pallet and lifted from the now-formed pipe. A new pallet is then added to the jacket and the form is returned to the filling station and lowered over the core.
There are numerous, obvious advantages to a multiple station machine since production rates can be substantially increased and size changeovers can be quickly made. The forms at each of the three stations can be of either different diameters of the same size. In an effort to increase production rates, some machines have a cluster of forms at a single station, but all machines of this type strip both the jacket and core at the forming station with the formed, uncured pipes being moved to the curing area while still wet and not secured. Since the stripping step is the most time consuming step in the pipe making process, further increased productivity could be accomplished if a multiple form set could be combined into a single module with means being provided to strip all forms in a module simultaneously without the necessity of modifying the standard feeding, pressure heading and stripping equipment. However, there is not known a machine which has these features.
Also, if a multiple-form per module type machine is to be used, it would also be desirable to simplify the stripping operation by eliminating vibrator cord handling on the jackets.
It is therefore the principal object of the invention to provide a multiple station pipe forming machine which couples multiple form sets into a single module at each station thus substantially increasing the production output with no increase in machine manpower.